JPH10198162A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive developing device having simple constitution capable of preventing not only toner scattering but also the deterioration of image quality by completely abutting all the area of a sheet member (entrance seal) on a photoreceptor drum under various circumstances. SOLUTION: This developing device is equipped with the flexible sheet member 3 provided with extended parts 3c extended in the rotating direction of the photoreceptor drum 1 at both ends of an area 3a spreading in the axial direction of the drum 1 so as to cover the drum 1 and abutting on the drum 1 in the longitudinal direction. The internal angle part G of the sheet member 3 formed between the area 3a and the part 3c is circular-arc shaped. In the case of assuming lines J parallel with a line I perpendicular to the abutting ridge line 3b of the area 3a on the parts 3c at both ends in a state where the member 3 is developed before it is set in the developing device, the leading edge sides of both assumed lines J are inclined to approach the inside when the member 3 is set in the developing device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used for an image forming apparatus such as a copying machine, a facsimile, a printer, etc., and more particularly to a developing device having an improved entrance seal for preventing toner scattering and the like. .

[0002]

2. Description of the Related Art Conventionally, in a developing device using a two-component developer, toner is supplied from a magnetic brush of a developing roller disposed in parallel and close to the photosensitive drum, and is formed on the photosensitive drum. In general, a toner image is formed by visualizing an electrostatic latent image. However, a part of the toner supplied from the magnetic brush may be scattered and contaminate each device in the machine, resulting in a problem that the image quality of the toner image is deteriorated.

For this reason, a space near the developing area between the photosensitive drum and the developing roller is closed by a flexible sheet member called an “entrance seal”. FIG. 6 shows an example of the configuration. In FIG. 1, a developing roller 2 is arranged in proximity to a photosensitive drum 1, and one end is fixed to a supporting member 4 located above the developing roller 2 with a double-sided tape 5, and a tip end portion of the photosensitive drum 1 is fixed. An inlet seal 30 is provided, which is arranged toward the inlet. A is a development area. This entrance seal 3
Numeral 0 indicates that the leading end of the photosensitive drum 1 is in contact with the photosensitive drum 1, so that the toner is not scattered upward, so that the photosensitive drum 1 is always rubbed even during rotation to eliminate a gap. Although there is a gap B between the developing device case 6 and the photosensitive drum 1, the surface of the drum 1 on which the toner image has been formed cannot be rubbed with a sheet member or the like, and must be opened. Nevertheless, the gap B is made as small as possible to minimize scattering.

At the end of the magnetic brush formed on the developing roller 2, not only the toner scatters, but also the carrier is easily detached from the brush ears. When the carrier leaves, it falls,
The inside of the machine and other devices may be soiled, and a good image may not be obtained. Therefore, the end of the developing roller 2 also needs to be closed. In order to close this end, a member dedicated to closing is often provided separately from the inlet seal 30, rather than separately provided, which is more cost-effective and easier to assemble. Because it is advantageous. Specifically, as shown in FIG. 7, a contact portion 30a of the entrance seal 30, which is a region contacting the surface of the photosensitive drum 1, is arranged in parallel with the photosensitive drum 1, and the contact ridge line 30b
Abuts on the photosensitive drum 1, and at both ends thereof, there are provided extended portions 30c formed to extend in the rotation direction of the photosensitive drum 1. In order to see the correspondence of the entrance seal 30 in the longitudinal direction, the developing roller 2 is drawn on the lower side in the figure, and 7 is a magnetic brush formed on the developing roller 2.

However, the width e of the contact portion 30a of the entrance seal 30 is set to be larger than the developing area (not shown) of the photosensitive drum 1 and smaller than the width c of the spike of the magnetic brush 7. I have. With this configuration, the inlet seal 3
The extended portion 3c of 0 covers both ends of the magnetic brush 7 to prevent the above-mentioned toner scattering and carrier drop due to carrier separation.

FIG. 8 shows the contact state when the seal width a of the inlet seal 30 shown in FIG. 7 is changed in the installation state of FIG. The figure shows the photosensitive drum 1
Members other than the and the inlet seal 30 are omitted. 6A shows the same installation state as that of FIG. 6, and is installed at an angle θ from one end P of the entrance seal 30 with respect to the vertical direction, and the other end is in contact with the surface of the photosensitive drum 1 at Q ₁ . This shows a state of contact. From this state, the entrance seal 30
Without changing the position of one end P and the installation angle θ, the seal width a is gradually increased to a ₁ → a ₂ → a ₃ → a ₄ (a ₁ <a ₂ <a ₃ <a ₄ ). Then, the manner of contact of the entrance seal 30 changes in the order of FIG. 3A → (B) → (C) → (D).
What was abutted at its distal end Q ₁ to have gradually so as to draw an arc, it will come to abut in their abdomen. In the same figure (D), in the state of complete abdominal contact,
Inlet seal 30 at Q ₄ are, the photosensitive drum 1 at that point
It is in a state of substantially overlapping the tangent of the surface. The position of Q ₄ in this state is on a line connecting the developing roller 2 around a substantially photosensitive drum 1 center. If the seal width is a ₄ or more, the abdomen contact at the same position as the Q ₄ in all the drawing (D).

When the entrance seal 30 has a shape as shown in FIG. 7, the length in the direction toward the photosensitive drum 1 is, as shown in FIG. it is believed that a combination of length, because the sealing width a is the magnitude of a ₁ shown in FIG. 8 (a), extension length b is to cover the entire developing roller second end, FIG. (D )
Is a ₄ or more dimensions shown. Therefore, the manner of contact is naturally different between the contact portion 30a and the extended portion 30c, and the contact portion 30a tends to be in the same manner as in FIG. Therefore, as shown in FIG. 7, the photosensitive drum 1 is changed so that the vicinity of the inner angle F, which is the joint between the contact portion 30a and the extension portion 30c, continuously changes from the state shown in FIG. 7A to the state shown in FIG. Will be hit. Therefore, when the inner angle F is a right angle as shown in FIG. 7, the inner angle F does not contact the entire surface of the drum 1 which is a curved surface, and does not contact the entire surface. Will cause.

Conventionally, in order to solve this problem, as shown in FIG. 9, an inlet seal 31 having an inner angle F ′ in which the shape of the inner angle F is gradually changed is used, as shown in FIG. I was trying to make no gap.

[0009]

However, in the above-described method in which the shape of the inner angle F of the entrance seal 30 in the conventional developing device is devised, since it is actually formed by trial and error, the curved surface of the photosensitive drum 1 is formed. It is difficult to find an optimum shape that can be brought into contact with the entire surface and that can cope with various situations such as a dimensional error of the peripheral parts related to the installation of the inlet seal 31 and a displacement of the assembly. In other words, the entrance seal 3
Therefore, there is a problem that high dimensional accuracy is required for itself 1 and the peripheral parts, and there is not much margin for assembling displacement of the inlet seal 31 and the peripheral parts. Accordingly, the present invention solves the above-mentioned conventional problems, and in various situations such as a dimensional error of a peripheral part and a displacement of an assembly, the whole area of the entrance seal abuts on the photosensitive drum without causing toner scattering. It is an object of the present invention to provide a low-cost, simple-structure developing device that can completely prevent the image quality and, as a result, can prevent the image quality from lowering.

[0010]

According to an aspect of the present invention, there is provided a developing roller for supplying toner to a photosensitive drum, and the photosensitive roller for preventing toner from scattering from the developing roller. A core that extends in the axial direction of the drum and closes the vicinity of the developing area on the body drum, and has extension portions that extend in the drum rotation direction at both ends of a region that contacts the photosensitive drum in the longitudinal direction. In a developing device provided with a U-shaped, flexible sheet member, the sheet member has an arc-shaped inner corner formed between an area in contact with the photosensitive drum and the extended portion. In the unfolded state before installing the sheet member in the developing device, when a straight line parallel to a straight line perpendicular to the contact ridge line of the contact area is assumed on the extended portions at both ends, The door member when installed in the developing device is that both the distal end side of the assumed line is in a state inclined so as to approach both inward.

According to a second aspect of the present invention, a developing roller for supplying toner to the photosensitive drum and, in order to prevent toner from scattering from the developing roller, extend in the vicinity of a developing area on the photosensitive drum in the axial direction of the drum. And occlude,
A U-shaped, flexible sheet member having an extended portion extending in the direction of rotation of the drum at both ends of a region in contact with the photosensitive drum in the longitudinal direction, the developing device comprising: The member has an arc-shaped inner corner formed between the area contacting the photoconductor drum and the extended portion, and the sheet member has an extended portion at both ends and an inner side on the inner corner side. That is, the sides are inclined so as to be closer to the photosensitive drum than the outer sides.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. The basic configuration and arrangement of the developing device and the photosensitive drum according to the present invention are the same as those shown in FIG. In the present invention, an entrance seal 3 as shown in FIG. 1 is used instead of the entrance seal 30 which is a sheet member shown in FIG. This inlet seal 3
As shown in the drawing, the photosensitive drum 1 (see FIG.
A), and an extended portion 3c formed on both ends of the contact portion 3a so as to extend in the rotation direction of the photosensitive drum 1, and an inner corner G of a joint between the two portions.
Has a simple arc shape. The size of the diameter R of the arc varies depending on the diameter of the photosensitive drum 1 and the installation position of the entrance seal 3. For example, with respect to the photosensitive drum 1 having a diameter of 30 mm, the entrance seal has a positional relationship as shown in FIG. 3
Is set, the diameter R is suitably about 5 to 10 mm, and may be appropriately determined within this range.

Here, a straight line I perpendicular to the ridge line 3b of the entrance seal 3 contacting the photosensitive drum 1 is considered at an arbitrary point in the contact area, and a straight line J parallel to the straight line J is formed on both of the extended portions 3.
Assume on c. When the inlet seal 3 is installed in the developing device (see FIG. 6), as shown in FIG. 2, it is installed such that the assumed straight lines J are inclined inward so that the leading ends of the straight lines J approach each other. Specifically, in the unfolded state of FIG. 1, the distance e ₁ between the inner ends KK ′ of the extended portions 3c at both ends.
However, after installation in the developing device, the distance e ₂ (e ₁ >) shown in FIG.
e ₂ ).

Assuming that the front side of the drawing is the photosensitive drum 1 side when the entrance seal 3 is actually installed, such a setting results in a convex state in which the vicinity of the inner corner G rises toward the front side of the drawing. The arc shape follows and closely adheres to the curved surface of the photosensitive drum 1, and the gap with the photosensitive drum 1 is completely eliminated. The extent to which the extension portion 3c is inclined, when represented by the inclination distance f shown in FIG. 2, depends on the extension portion length b shown in FIG. 7. For example, if b = 40 (mm), the inclination distance f About 1 to 3 mm is appropriate. Depending on the conditions, the dimensions may be other than these, but since only the inclination is changed, the optimum degree can be easily searched.

As a method of inclining the extension portion 3c, as shown in FIG. 3, a support member 4 on which the entrance seal 3 is provided is provided with an installation reference 5 such as a line or a step, and the installation reference 5 is the same. As shown in the drawing, it may be provided in advance so as to be inclined, and the outer end lines 3d of both ends of the inlet seal 3 shown in FIG. In FIG. 3, reference numeral 2 denotes a developing roller. Alternatively, the installation reference (not shown) of the support member 4 is vertical, but as shown in FIG.
The second expanded original shape, leave shape obtained by inclining the both ends outline 32d to be flared, and, from the distance between the inter-end distance e ₄ extension portions 32c installation standards of the supporting member 4 There is also a method in which, when fixing to the support member 4, the convex shape is formed by fixing it to the support member 4 so as to conform to the curved surface of the photosensitive drum 1, thereby sealing the photosensitive drum 1.

Further, a notch or a hole is provided on both of the extended portions 3c of the inlet seal 3 at a distance ex (not shown), and the support member 4 is fitted to the cutout or the hole.
And a projection or the like is provided with the distance between them as ey, and the distance ex>
If the distance ey is set, when the inlet seal 3 is installed on the support member 4, the extension 3
c both approach the inside, and have the same effect as in the above embodiment.

Next, an embodiment based on claim 2 will be described with reference to FIG. FIG. 1 is a view in which the vicinity of the developing area of the photosensitive drum 1 is cut by a plane passing through the developing roller 2 and the rotation axis of the photosensitive drum 1. In this embodiment, the developing roller 2 is disposed so as to face the photosensitive drum 1. The member surrounding the developing roller 2 becomes a support member 4 for fixing the entrance seal 3.
An extension 3c of the inlet seal 3 of the support member 4 (FIG. 1)
The fixing portion 4a for fixing the fixing member 4a is inclined so that both inner ends thereof approach the photosensitive drum 1, and an extension 3c of the entrance seal 3 is attached to the fixing portion 4a with a double-sided tape. Is fixed.

According to this configuration, the inner sides of the two extended portions 3c on the inner angle side are arranged so as to be inclined such that the inner sides closer to the photosensitive drum 1 than the outer sides, and the inner corners on both sides thereof are located on the photosensitive drum 1 side. Since the projection has a convex shape, the arc shape of the inner corner portion follows the curved surface of the photosensitive drum 1 and the contact ridge line is completely adhered. Also in this embodiment, the contact state is adjusted by selecting an appropriate numerical value for the arc-shaped diameter R (see FIG. 1) of the inlet seal 3 and appropriately selecting the inclination of the fixing portion 4a of the support member 4. be able to.

[0019]

As described above, according to the first aspect, the sheet member has an arc-shaped inner angle formed between the area contacting the photosensitive drum and the extended portion. In the unfolded state before the member is installed in the developing device, when a straight line parallel to a straight line perpendicular to the contact ridge line of the contact area is assumed on the extended portions at both ends, the sheet member is used as the developing device. When it is installed in, the tip side of both the assumed lines are in a state of being inclined so as to approach inward together, so a sheet member of a simple shape,
The contact with the photoreceptor drum can be made completely without any gap, and the scattering of toner can be prevented without requiring the dimensional accuracy and assembly accuracy of the sheet member and its peripheral parts. As a result, it is possible to prevent the inside of the device and each device from being stained, and to prevent the image quality from being lowered.

According to the present invention, the developing roller for supplying the toner to the photosensitive drum and the electrostatic latent image formed on the photosensitive drum are used to prevent the toner from scattering from the developing roller. A portion that extends in the axial direction of the drum and closes the vicinity of the development region for visualization, and extends in the drum rotation direction at both ends of a region that contacts the photosensitive drum in the longitudinal direction. Since it has a U-shaped and flexible sheet member, the same effects as those of claim 1 can be obtained.

[Brief description of the drawings]

FIG. 1 is a development view showing an embodiment of a sheet member assembled to a developing device of the present invention.

FIG. 2 is an explanatory view showing a state where the sheet member of FIG. 1 is assembled to a developing device.

FIG. 3 is a configuration diagram illustrating a support member provided with an installation reference.

FIG. 4 is a development view showing a sheet member having a shape in which both ends of an extended portion are flared.

FIG. 5 is a view showing an embodiment based on claim 2, and is a schematic sectional view of the vicinity of the developing area of the photosensitive drum cut along a plane passing through the rotation axis of the developing roller and the photosensitive drum.

FIG. 6 is a schematic configuration diagram showing an arrangement configuration of a conventional developing device and a photosensitive drum.

FIG. 7 is an explanatory diagram showing a positional relationship between a conventional sheet member and a developing roller.

FIG. 8 is an explanatory view showing a conventional state in which sheet members having various lengths are in contact with a photosensitive drum.

FIG. 9 is a development view showing a conventional seat member in which the shape of the inner angle of the joint between the contact area and the extension part is improved.

[Description of Signs] 1 photosensitive drum 2 developing roller 3 sheet member 3a contact area 3b contact ridge 3c extension

Claims (2)

[Claims] A developing roller for supplying toner to the photosensitive drum, and a visualizing means for visualizing an electrostatic latent image formed on the photosensitive drum in order to prevent toner from scattering from the developing roller. And extending in the axial direction of the drum and closing the vicinity of the developing region, and having a U-shape having extended portions extending in the drum rotation direction at both ends of a region abutting on the photosensitive drum in the longitudinal direction. A developing device provided with a flexible sheet member, wherein the sheet member has an arc-shaped inner corner formed between an area in contact with the photosensitive drum and the extended portion. In a developed state before the sheet member is installed in the developing device, when a straight line parallel to a straight line perpendicular to the contact ridge line of the contact area is assumed on the extended portions at both ends, the sheet member is developed. Equipment The developing device is characterized in that when it is placed, the tip sides of both the assumed lines are inclined so as to approach inward. A developing roller for supplying toner to the photosensitive drum; and a visualizing means for visualizing an electrostatic latent image formed on the photosensitive drum in order to prevent toner from scattering from the developing roller. And extending in the axial direction of the drum and closing the vicinity of the developing region, and having a U-shape having extended portions extending in the drum rotation direction at both ends of a region abutting on the photosensitive drum in the longitudinal direction. A developing device having a flexible sheet member, wherein the sheet member has an arc-shaped inner corner formed between an area in contact with the photosensitive drum and the extended portion, and , This sheet member, the extended portions of both ends,
The developing device is characterized in that the inner side on the inner corner side is inclined so as to be closer to the photosensitive drum than the outer side.